Integrated display device and sensing device with force sensing

ABSTRACT

An example integrated display device and capacitive sensing device having an input surface includes a plurality of sensor electrodes. Each of the plurality of sensor electrodes includes at least one common electrode configured for display updating and capacitive sensing. The device further includes at least one conductive electrode, wherein the plurality of sensor electrodes are disposed between the input surface and the at least one conductive electrode and wherein the plurality of sensor electrodes are configured to deflect toward the conductive electrode. The device further includes a processing system, coupled to the plurality of sensor electrodes, configured to detect changes in absolute capacitance of at least a portion of the plurality of sensor electrodes, and determine force information for an input object based on the changes in absolute capacitance.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationSer. No. 62/160,554, filed May 12, 2015, which is incorporated byreference herein in its entirety.

BACKGROUND

Field of the Disclosure

Embodiments of disclosure generally relate to capacitive sensing and,more particularly, an integrated display device and sensing device withforce sensing.

Description of the Related Art

Input devices including proximity sensor devices (also commonly calledtouchpads or touch sensor devices) are widely used in a variety ofelectronic systems. A proximity sensor device typically includes asensing region, often demarked by a surface, in which the proximitysensor device determines the presence, location and/or motion of one ormore input objects. Proximity sensor devices may be used to provideinterfaces for the electronic system. For example, proximity sensordevices are often used as input devices for larger computing systems(such as opaque touchpads integrated in, or peripheral to, notebook ordesktop computers). Proximity sensor devices are also often used insmaller computing systems (such as touch screens integrated in cellularphones).

SUMMARY

Techniques for force sensing in an integrated display and capacitivesensing device are described. In an embodiment, an integrated displaydevice and capacitive sensing device having an input surface includes aplurality of sensor electrodes. Each of the plurality of sensorelectrodes includes at least one common electrode configured for displayupdating and capacitive sensing. The device further includes at leastone conductive electrode, wherein the plurality of sensor electrodes aredisposed between the input surface and the at least one conductiveelectrode and wherein the plurality of sensor electrodes are configuredto deflect toward the conductive electrode. The device further includesa processing system, coupled to the plurality of sensor electrodes,configured to detect changes in absolute capacitance of at least aportion of the plurality of sensor electrodes, and determine forceinformation for an input object based on the changes in absolutecapacitance.

In another embodiment, a processing system for an integrated displaydevice and capacitive sensing device having an input surface includes asensor module comprising sensor circuitry configured to operate aplurality of sensor electrodes, each of the plurality of sensorelectrodes comprising at least one common electrode configured fordisplay updating and capacitive sensing. The processing system furtherincludes a processing module, coupled to the sensor circuitry,configured to detect changes in absolute capacitance of at least aportion of the plurality of sensor electrodes, and determine forceinformation for an input object based on the changes in absolutecapacitance, wherein the plurality of sensor electrodes are disposedbetween the input surface and at least one conductive electrode andwherein the plurality of sensor electrodes are configured to deflecttoward the conductive electrode.

In another embodiment, a method of operating an integrated displaydevice and capacitive sensing device having an input surface includesoperating a plurality of sensor electrodes for capacitive sensing, eachof the plurality of sensor electrodes comprising at least one commonelectrode configured for display updating and the capacitive sensing,wherein the plurality of sensor electrodes are disposed between theinput surface and at least one conductive electrode and wherein theplurality of sensor electrodes are configured to deflect toward theconductive electrode. The method further includes detecting changes inabsolute capacitance of at least a portion of the plurality of sensorelectrodes. The method further includes determining force informationfor an input object based on the changes in absolute capacitance, theforce causing at least a portion of the plurality of sensor electrodesto deflect towards at least one electrode disposed below and spacedapart from the plurality of sensor electrodes.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentinvention can be understood in detail, a more particular description ofthe invention, briefly summarized above, may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlytypical embodiments of this invention and are therefore not to beconsidered limiting of its scope, for the invention may admit to otherequally effective embodiments.

FIG. 1 is a block diagram of an exemplary input device, according to oneembodiment described herein.

FIGS. 2A-2B illustrate portions of exemplary patterns of sensingelements according to embodiments described herein.

FIG. 3 is a block diagram depicting a cross-section of an input deviceaccording to an embodiment.

FIG. 4 is a block diagram depicting a cross-section of a display cellaccording to an embodiment.

FIG. 5 is a block diagram depicting a cross-section of an input deviceaccording to another embodiment.

FIG. 6 is a schematic cross-section depicting a force applied to aninput device by an input object according to an embodiment.

FIG. 7 is a top view of the input device of FIG. 6 given the appliedforce.

FIG. 8 is a flow diagram depicting a method of operating an integrateddisplay device and capacitive sensing device according to an embodiment.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. It is contemplated that elements disclosed in oneembodiment may be beneficially utilized on other embodiments withoutspecific recitation. The drawings referred to here should not beunderstood as being drawn to scale unless specifically noted. Also, thedrawings are often simplified and details or components omitted forclarity of presentation and explanation. The drawings and discussionserve to explain principles discussed below, where like designationsdenote like elements.

DETAILED DESCRIPTION

FIG. 1 is a block diagram of an exemplary input device 100, inaccordance with embodiments of the invention. The input device 100 maybe configured to provide input to an electronic system (not shown). Asused in this document, the term “electronic system” (or “electronicdevice”) broadly refers to any system capable of electronicallyprocessing information. Some non-limiting examples of electronic systemsinclude personal computers of all sizes and shapes, such as desktopcomputers, laptop computers, netbook computers, tablets, web browsers,e-book readers, and personal digital assistants (PDAs). Additionalexample electronic systems include composite input devices, such asphysical keyboards that include input device 100 and separate joysticksor key switches. Further example electronic systems include peripheralssuch as data input devices (including remote controls and mice), anddata output devices (including display screens and printers). Otherexamples include remote terminals, kiosks, and video game machines(e.g., video game consoles, portable gaming devices, and the like).Other examples include communication devices (including cellular phones,such as smart phones), and media devices (including recorders, editors,and players such as televisions, set-top boxes, music players, digitalphoto frames, and digital cameras). Additionally, the electronic systemcould be a host or a slave to the input device.

The input device 100 can be implemented as a physical part of theelectronic system, or can be physically separate from the electronicsystem. As appropriate, the input device 100 may communicate with partsof the electronic system using any one or more of the following: buses,networks, and other wired or wireless interconnections. Examples includeI²C, SPI, PS/2, Universal Serial Bus (USB), Bluetooth, RF, and IRDA.

In FIG. 1, the input device 100 is shown as a proximity sensor device(also often referred to as a “touchpad” or a “touch sensor device”)configured to sense input provided by one or more input objects 140 in asensing region 120. Example input objects include fingers and styli, asshown in FIG. 1.

Sensing region 120 encompasses any space above, around, in and/or nearthe input device 100 in which the input device 100 is able to detectuser input (e.g., user input provided by one or more input objects 140).The sizes, shapes, and locations of particular sensing regions may varywidely from embodiment to embodiment. In some embodiments, the sensingregion 120 extends from a surface of the input device 100 in one or moredirections into space until signal-to-noise ratios prevent sufficientlyaccurate object detection. The distance to which this sensing region 120extends in a particular direction, in various embodiments, may be on theorder of less than a millimeter, millimeters, centimeters, or more, andmay vary significantly with the type of sensing technology used and theaccuracy desired. Thus, some embodiments sense input that comprises nocontact with any surfaces of the input device 100, contact with an inputsurface (e.g. a touch surface) of the input device 100, contact with aninput surface of the input device 100 coupled with some amount ofapplied force or pressure, and/or a combination thereof. In variousembodiments, input surfaces may be provided by surfaces of casingswithin which the sensor electrodes reside, by face sheets applied overthe sensor electrodes or any casings, etc. In some embodiments, thesensing region 120 has a rectangular shape when projected onto an inputsurface of the input device 100.

The input device 100 may utilize any combination of sensor componentsand sensing technologies to detect user input in the sensing region 120.The input device 100 comprises one or more sensing elements fordetecting user input. As several non-limiting examples, the input device100 may use capacitive, elastive, resistive, inductive, magnetic,acoustic, ultrasonic, and/or optical techniques.

Some implementations are configured to provide images that span one,two, three, or higher dimensional spaces. Some implementations areconfigured to provide projections of input along particular axes orplanes.

In some capacitive implementations of the input device 100, voltage orcurrent is applied to create an electric field. Nearby input objectscause changes in the electric field, and produce detectable changes incapacitive coupling that may be detected as changes in voltage, current,or the like.

Some capacitive implementations utilize arrays or other regular orirregular patterns of capacitive sensing elements to create electricfields. In some capacitive implementations, separate sensing elementsmay be ohmically shorted together to form larger sensor electrodes. Somecapacitive implementations utilize resistive sheets, which may beuniformly resistive.

Some capacitive implementations utilize “self capacitance” (or “absolutecapacitance”) sensing methods based on changes in the capacitivecoupling between sensor electrodes and an input object. In variousembodiments, an input object near the sensor electrodes alters theelectric field near the sensor electrodes, thus changing the measuredcapacitive coupling. In one implementation, an absolute capacitancesensing method operates by modulating sensor electrodes with respect toa reference voltage (e.g. system ground), and by detecting thecapacitive coupling between the sensor electrodes and input objects.

Some capacitive implementations utilize “mutual capacitance” (or“transcapacitance”) sensing methods based on changes in the capacitivecoupling between sensor electrodes. In various embodiments, an inputobject near the sensor electrodes alters the electric field between thesensor electrodes, thus changing the measured capacitive coupling. Inone implementation, a transcapacitive sensing method operates bydetecting the capacitive coupling between one or more transmitter sensorelectrodes (also “transmitter electrodes” or “transmitters”) and one ormore receiver sensor electrodes (also “receiver electrodes” or“receivers”). Transmitter sensor electrodes may be modulated relative toa reference voltage (e.g., system ground) to transmit transmittersignals. Receiver sensor electrodes may be held substantially constantrelative to the reference voltage to facilitate receipt of resultingsignals. A resulting signal may comprise effect(s) corresponding to oneor more transmitter signals, and/or to one or more sources ofenvironmental interference (e.g. other electromagnetic signals). Sensorelectrodes may be dedicated transmitters or receivers, or may beconfigured to both transmit and receive.

In FIG. 1, a processing system 110 is shown as part of the input device100. The processing system 110 is configured to operate the hardware ofthe input device 100 to detect input in the sensing region 120. Theprocessing system 110 comprises parts of or all of one or moreintegrated circuits (ICs) and/or other circuitry components. Forexample, a processing system for a mutual capacitance sensor device maycomprise transmitter circuitry configured to transmit signals withtransmitter sensor electrodes, and/or receiver circuitry configured toreceive signals with receiver sensor electrodes). In some embodiments,the processing system 110 also comprises electronically-readableinstructions, such as firmware code, software code, and/or the like. Insome embodiments, components composing the processing system 110 arelocated together, such as near sensing element(s) of the input device100. In other embodiments, components of processing system 110 arephysically separate with one or more components close to sensingelement(s) of input device 100, and one or more components elsewhere.For example, the input device 100 may be a peripheral coupled to adesktop computer, and the processing system 110 may comprise softwareconfigured to run on a central processing unit of the desktop computerand one or more ICs (perhaps with associated firmware) separate from thecentral processing unit. As another example, the input device 100 may bephysically integrated in a phone, and the processing system 110 maycomprise circuits and firmware that are part of a main processor of thephone. In some embodiments, the processing system 110 is dedicated toimplementing the input device 100. In other embodiments, the processingsystem 110 also performs other functions, such as operating displayscreens, driving haptic actuators, etc.

The processing system 110 may be implemented as a set of modules thathandle different functions of the processing system 110. Each module maycomprise circuitry that is a part of the processing system 110,firmware, software, or a combination thereof. In various embodiments,different combinations of modules may be used. Example modules includehardware operation modules for operating hardware such as sensorelectrodes and display screens, data processing modules for processingdata such as sensor signals and positional information, and reportingmodules for reporting information. Further example modules includesensor operation modules configured to operate sensing element(s) todetect input, identification modules configured to identify gesturessuch as mode changing gestures, and mode changing modules for changingoperation modes.

In some embodiments, the processing system 110 responds to user input(or lack of user input) in the sensing region 120 directly by causingone or more actions. Example actions include changing operation modes,as well as GUI actions such as cursor movement, selection, menunavigation, and other functions. In some embodiments, the processingsystem 110 provides information about the input (or lack of input) tosome part of the electronic system (e.g. to a central processing systemof the electronic system that is separate from the processing system110, if such a separate central processing system exists). In someembodiments, some part of the electronic system processes informationreceived from the processing system 110 to act on user input, such as tofacilitate a full range of actions, including mode changing actions andGUI actions.

For example, in some embodiments, the processing system 110 operates thesensing element(s) of the input device 100 to produce electrical signalsindicative of input (or lack of input) in the sensing region 120. Theprocessing system 110 may perform any appropriate amount of processingon the electrical signals in producing the information provided to theelectronic system. For example, the processing system 110 may digitizeanalog electrical signals obtained from the sensor electrodes. Asanother example, the processing system 110 may perform filtering orother signal conditioning. As yet another example, the processing system110 may subtract or otherwise account for a baseline, such that theinformation reflects a difference between the electrical signals and thebaseline. As yet further examples, the processing system 110 maydetermine positional information, recognize inputs as commands,recognize handwriting, and the like.

“Positional information” as used herein broadly encompasses absoluteposition, relative position, velocity, acceleration, and other types ofspatial information. Exemplary “zero-dimensional” positional informationincludes near/far or contact/no contact information. Exemplary“one-dimensional” positional information includes positions along anaxis. Exemplary “two-dimensional” positional information includesmotions in a plane. Exemplary “three-dimensional” positional informationincludes instantaneous or average velocities in space. Further examplesinclude other representations of spatial information. Historical dataregarding one or more types of positional information may also bedetermined and/or stored, including, for example, historical data thattracks position, motion, or instantaneous velocity over time.

In some embodiments, the input device 100 is implemented with additionalinput components that are operated by the processing system 110 or bysome other processing system. These additional input components mayprovide redundant functionality for input in the sensing region 120, orsome other functionality. FIG. 1 shows buttons 130 near the sensingregion 120 that can be used to facilitate selection of items using theinput device 100. Other types of additional input components includesliders, balls, wheels, switches, and the like. Conversely, in someembodiments, the input device 100 may be implemented with no other inputcomponents.

In some embodiments, the input device 100 comprises a touch screeninterface, and the sensing region 120 overlaps at least part of anactive area of a display screen. For example, the input device 100 maycomprise substantially transparent sensor electrodes overlaying thedisplay screen and provide a touch screen interface for the associatedelectronic system. The display screen may be any type of dynamic displaycapable of displaying a visual interface to a user, and may include anytype of light emitting diode (LED), organic LED (OLED), cathode ray tube(CRT), liquid crystal display (LCD), plasma, electroluminescence (EL),or other display technology. The input device 100 and the display screenmay share physical elements. For example, some embodiments may utilizesome of the same electrical components for displaying and sensing. Asanother example, the display screen may be operated in part or in totalby the processing system 110.

It should be understood that while many embodiments of the invention aredescribed in the context of a fully functioning apparatus, themechanisms of the present invention are capable of being distributed asa program product (e.g., software) in a variety of forms. For example,the mechanisms of the present invention may be implemented anddistributed as a software program on information bearing media that arereadable by electronic processors (e.g., non-transitorycomputer-readable and/or recordable/writable information bearing mediareadable by the processing system 110). Additionally, the embodiments ofthe present invention apply equally regardless of the particular type ofmedium used to carry out the distribution. Examples of non-transitory,electronically readable media include various discs, memory sticks,memory cards, memory modules, and the like. Electronically readablemedia may be based on flash, optical, magnetic, holographic, or anyother storage technology.

FIG. 2A illustrates a portion of an exemplary pattern of sensingelements according to some embodiments. For clarity of illustration anddescription, FIG. 2A shows the sensing elements in a pattern of simplerectangles and does not show various components, such as variousinterconnects between the sensing elements and the processing system110. An electrode pattern 250A comprises a first plurality of sensorelectrodes 260 (260-1, 260-2, 260-3, . . . 260-n), and a secondplurality of sensor electrodes 270 (270-1, 270-2, 270-3, . . . 270-m)disposed over the first plurality of electrodes 260. In the exampleshown, n=m=4, but in general n and m are each positive integers and notnecessarily equal to each other. In various embodiments, the firstplurality of sensor electrodes 260 are operated as a plurality oftransmitter electrodes (referred to specifically as “transmitterelectrodes 260”), and the second plurality of sensor electrodes 270 areoperated as a plurality of receiver electrodes (referred to specificallyas “receiver electrodes 270”). In another embodiment, one plurality ofsensor electrodes may be configured to transmit and receive and theother plurality of sensor electrodes may also be configured to transmitand receive. Further processing system 110 receives resulting signalswith one or more sensor electrodes of the first and/or second pluralityof sensor electrodes while the one or more sensor electrodes aremodulated with absolute capacitive sensing signals. The first pluralityof sensor electrodes 260, the second plurality of sensor electrodes 270,or both can be disposed within the sensing region 120. The electrodepattern 250A can be coupled to the processing system 110.

The first plurality of electrodes 260 and the second plurality ofelectrodes 270 are typically ohmically isolated from each other. Thatis, one or more insulators separate the first plurality of electrodes260 and the second plurality of electrodes 270 and prevent them fromelectrically shorting to each other. In some embodiments, the firstplurality of electrodes 260 and the second plurality of electrodes 270are separated by insulative material disposed between them at cross-overareas; in such constructions, the first plurality of electrodes 260and/or the second plurality of electrodes 270 can be formed with jumpersconnecting different portions of the same electrode. In someembodiments, the first plurality of electrodes 260 and the secondplurality of electrodes 270 are separated by one or more layers ofinsulative material. In such embodiments, the first plurality ofelectrodes 260 and the second plurality of electrodes 270 can bedisposed on separate layers of a common substrate. In some otherembodiments, the first plurality of electrodes 260 and the secondplurality of electrodes 270 are separated by one or more substrates; forexample, the first plurality of electrodes 260 and the second pluralityof electrodes 270 can be disposed on opposite sides of the samesubstrate, or on different substrates that are laminated together. Insome embodiments, the first plurality of electrodes 260 and the secondplurality of electrodes 270 can be disposed on the same side of a singlesubstrate.

The areas of localized capacitive coupling between the first pluralityof sensor electrodes 260 and the second plurality sensor electrodes 270may be form “capacitive pixels” of a “capacitive image.” The capacitivecoupling between sensor electrodes of the first and second pluralities260 and 270 changes with the proximity and motion of input objects inthe sensing region 120. Further, in various embodiments, the localizedcapacitive coupling between each of the first plurality of sensorelectrodes 260 and the second plurality of sensor electrodes 270 and aninput object may be termed “capacitive pixels” of a “capacitive image.”In some embodiments, the localized capacitive coupling between each ofthe first plurality of sensor electrodes 260 and the second plurality ofsensor electrodes 270 and an input object may be termed “capacitivemeasurements” of “capacitive profiles.”

The processing system 110 can include a sensor module 208 having sensorcircuitry 204. The sensor module 208 operates the electrode pattern 250Areceive resulting signals from electrodes in the electrode pattern usinga capacitive sensing signal having a sensing frequency. The processingsystem 110 can include a processing module 220 configured to determinecapacitive measurements from the resulting signals. The processingmodule 220 can include processor circuitry 222, such as a digital signalprocessor (DSP), microprocessor, or the like. The processing module 220can include software and/or firmware configured for execute by theprocessor circuitry 222 to implement the functions described herein.Alternatively, some or all of the functions of the processor module 220can be implemented entirely in hardware (e.g., using integratedcircuitry). The processing module 220 can track changes in capacitivemeasurements to detect input object(s) in the sensing region 120. Theprocessing system 110 can include other modular configurations, and thefunctions performed by the sensor module 208 and the processing module220 can, in general, be performed by one or more modules or circuits inthe processing system 110. The processing system 110 can include othermodules and circuits, and can perform other functions as described insome embodiments below.

The processing system 110 can operate in absolute capacitive sensingmode or transcapacitive sensing mode. In absolute capacitive sensingmode, receiver(s) in the sensor circuitry 204 measure voltage, current,or charge on sensor electrode(s) in the electrode pattern 250A while thesensor electrode(s) are modulated with absolute capacitive sensingsignals to generate the resulting signals. The processing module 220generates absolute capacitive measurements from the resulting signals.The processing module 220 can track changes in absolute capacitivemeasurements to detect input object(s) in the sensing region 120.

In transcapacitive sensing mode, transmitter(s) in the sensor circuitry204 drive one or more of the first plurality of electrodes 260 with thecapacitive sensing signal (also referred to as a transmitter signal ormodulated signal in the transcapacitive sensing mode). Receiver(s) inthe sensor circuitry 204 measure voltage, current, or charge on one ormore of the second plurality of electrodes 270 to generate the resultingsignals. The resulting signals comprise the effects of the capacitivesensing signal and input object(s) in the sensing region 120. Theprocessing module 220 generates transcapacitive measurements from theresulting signals. The processing module 220 can track changes intranscapacitive measurements to detect input object(s) in the sensingregion 120.

In some embodiments, the processing system 110 “scans” the electrodepattern 250A to determine capacitive measurements. In thetranscapacitive sensing mode, the processing system 110 can drive thefirst plurality of electrodes 260 to transmit transmitter signal(s). Theprocessing system 110 can operate the first plurality of electrodes 260such that one transmitter electrode transmits at one time, or multipletransmitter electrodes transmit at the same time. Where multipletransmitter electrodes transmit simultaneously, these multipletransmitter electrodes may transmit the same transmitter signal andeffectively produce a larger transmitter electrode, or these multipletransmitter electrodes may transmit different transmitter signals. Forexample, multiple transmitter electrodes may transmit differenttransmitter signals according to one or more coding schemes that enabletheir combined effects on the resulting signals of the second pluralityof electrodes 270 to be independently determined. In the absolutecapacitive sensing mode, the processing system 110 can receivingresulting signals from one sensor electrode 260, 270 at a time, or froma plurality of sensor electrodes 260, 270 at a time. In either mode, theprocessing system 110 can operate the second plurality of electrodes 270singly or collectively to acquire resulting signals. In absolutecapacitive sensing mode, the processing system 110 can concurrentlydrive all electrodes along one or more axes. In some examples, theprocessing system 110 can drive electrodes along one axis (e.g., alongthe first plurality of sensor electrodes 260) while electrodes alonganother axis are driven with a shield signal, guard signal, or the like.In some examples, some electrodes along one axis and some electrodesalong the other axis can be driven concurrently.

In the transcapacitive sensing mode, the processing system 110 can usethe resulting signals to determine capacitive measurements at thecapacitive pixels. A set of measurements from the capacitive pixels forma “capacitive image” (also “capacitive frame”) representative of thecapacitive measurements at the pixels. The processing system 110 canacquire multiple capacitive images over multiple time periods, and candetermine differences between capacitive images to derive informationabout input in the sensing region 120. For example, the processingsystem 110 can use successive capacitive images acquired over successiveperiods of time to track the motion(s) of one or more input objectsentering, exiting, and within the sensing region 120.

In absolute capacitive sensing mode, the processing system 110 can usethe resulting signals to determine capacitive measurements along an axisof the sensor electrodes 260 and/or an axis of the sensor electrodes270. A set of such measurements forms a “capacitive profile”representative of the capacitive measurements along the axis. Theprocessing system 110 can acquire multiple capacitive profiles along oneor both of the axes over multiple time periods and can determinedifferences between capacitive profiles to derive information aboutinput in the sensing region 120. For example, the processing system 110can use successive capacitive profiles acquired over successive periodsof time to track location or proximity of input objects within thesensing region 120. In other embodiments, each sensor can be acapacitive pixel of a capacitive image and the absolute capacitivesensing mode can be used to generate capacitive image(s) in addition toor in place of capacitive profiles.

The baseline capacitance of the input device 100 is the capacitive imageor capacitive profile associated with no input object in the sensingregion 120. The baseline capacitance changes with the environment andoperating conditions, and the processing system 110 can estimate thebaseline capacitance in various ways. For example, in some embodiments,the processing system 110 takes “baseline images” or “baseline profiles”when no input object is determined to be in the sensing region 120, anduses those baseline images or baseline profiles as estimates of baselinecapacitances. The processing module 220 can account for the baselinecapacitance in the capacitive measurements and thus the capacitivemeasurements can be referred to as “delta capacitive measurements”.Thus, the term “capacitive measurements” as used herein encompassesdelta-measurements with respect to a determined baseline.

In some touch screen embodiments, at least one of the first plurality ofsensor electrodes 260 and the second plurality of sensor electrodes 270comprise one or more display electrodes of a display device 280 used inupdating a display of a display screen, such as one or more segments ofa “Vcom” electrode (common electrodes), gate electrodes, sourceelectrodes, anode electrode and/or cathode electrode. These displayelectrodes may be disposed on an appropriate display screen substrate.For example, the display electrodes may be disposed on a transparentsubstrate (a glass substrate, TFT glass, or any other transparentmaterial) in some display screens (e.g., In Plane Switching (IPS) orPlane to Line Switching (PLS) Organic Light Emitting Diode (OLED)), onthe bottom of the color filter glass of some display screens (e.g.,Patterned Vertical Alignment (PVA) or Multi-domain Vertical Alignment(MVA)), over an emissive layer (OLED), etc. The display electrodes canalso be referred to as “combination electrodes,” since the displayelectrodes perform functions of display updating and capacitive sensing.In various embodiments, each sensor electrode of the first and secondplurality of sensor electrodes 260 and 270 comprises one or morecombination electrodes. In other embodiments, at least two sensorelectrodes of the first plurality of sensor electrodes 260 or at leasttwo sensor electrodes of the second plurality of sensor electrodes 270may share at least one combination electrode. Furthermore, in oneembodiment, both the first plurality of sensor electrodes 260 and thesecond plurality electrodes 270 are disposed within a display stack onthe display screen substrate. Additionally, at least one of the sensorelectrodes 260, 270 in the display stack may comprise a combinationelectrode. However, in other embodiments, only the first plurality ofsensor electrodes 260 or the second plurality of sensor electrodes 270(but not both) are disposed within the display stack, while other sensorelectrodes are outside of the display stack (e.g., disposed on anopposite side of a color filter glass).

In an embodiment, the processing system 110 comprises a singleintegrated controller, such as an application specific integratedcircuit (ASIC), having the sensor module 208, the processing module 220,and any other module(s) and/or circuit(s). In another embodiment, theprocessing system 110 can include a plurality of integrated circuits,where the sensor module 208, the processing module 220, and any othermodule(s) and/or circuit(s) can be divided among the integratedcircuits. For example, the sensor module 208 can be on one integratedcircuit, and the processing module 220 and any other module(s)and/circuit(s) can be one or more other integrated circuits. In someembodiments, a first portion of the sensor module 208 can be on oneintegrated circuit and a second portion of the sensor module 208 can beon second integrated circuit. In such embodiments, at least one of thefirst and second integrated circuits comprises at least portions ofother modules such as a display driver module and/or a display drivermodule.

FIG. 2B illustrates a portion of another exemplary pattern of sensingelements according to some embodiments. For clarity of illustration anddescription, FIG. 2B presents the sensing elements in a matrix ofrectangles and does not show various components, such as variousinterconnects between the processing system 110 and the sensingelements. An electrode pattern 250B comprises a plurality of sensorelectrodes 210 disposed in a rectangular matrix. The electrode pattern250B comprises sensor electrodes 210 _(J,K) (referred to collectively assensor electrodes 210) arranged in J rows and K columns, where J and Kare positive integers, although one or J and K may be zero. It iscontemplated that the electrode pattern 250B may comprise other patternsof the sensor electrodes 210, such as polar arrays, repeating patterns,non-repeating patterns, non-uniform arrays a single row or column, orother suitable arrangement. Further, the sensor electrodes 210 may beany shape, such as circular, rectangular, diamond, star, square,noncovex, convex, nonconcave concave, etc. Further, the sensorelectrodes 210 may be sub-divided into a plurality of distinctsub-electrodes. The electrode pattern 250 is coupled to the processingsystem 110.

The sensor electrodes 210 are typically ohmically isolated from oneanother. Additionally, where a sensor electrode 210 includes multiplesub-electrodes, the sub-electrodes may be ohmically isolated from eachother. Furthermore, in one embodiment, the sensor electrodes 210 may beohmically isolated from a grid electrode 218 that is between the sensorelectrodes 210. In one example, the grid electrode 218 may surround oneor more of the sensor electrodes 210, which are disposed in windows 216of the grid electrode 218. In some embodiments, the electrode pattern250B can include a plurality of grid electrodes 218. In someembodiments, the grid electrode 218 can include one or more segments.The grid electrode 218 may be used as a shield or to carry a guardingsignal for use when performing capacitive sensing with the sensorelectrodes 210. Alternatively or additionally, the grid electrode 218may be used as sensor electrode when performing capacitive sensing.Furthermore, the grid electrode 218 may be co-planar with the sensorelectrodes 210, but this is not a requirement. For instance, the gridelectrode 218 may be located on a different substrate or on a differentside of the same substrate as the sensor electrodes 210. The gridelectrode 218 is optional and in some embodiments, the grid electrode218 is not present.

In a first mode of operation, the processing system 110 can use at leastone sensor electrode 210 to detect the presence of an input object viaabsolute capacitive sensing. The sensor module 208 can measure voltage,charge, or current on sensor electrode(s) 210 to obtain resultingsignals indicative of a capacitance between the sensor electrode(s) 210and an input object. The processing module 220 uses the resultingsignals to determine absolute capacitive measurements. When theelectrode pattern 250B, the absolute capacitive measurements can be usedto form capacitive images.

In a second mode of operation, the processing system 110 can use groupsof the sensor electrodes 210 to detect presence of an input object viatranscapacitive sensing. The sensor module 208 can drive at least one ofthe sensor electrodes 210 with a transmitter signal, and can receive aresulting signal from at least one other of the sensor electrodes 210.The processing module 220 uses the resulting signals to determinetranscapacitive measurements and form capacitive images.

The input device 100 may be configured to operate in any one of themodes described above. The input device 100 may also be configured toswitch between any two or more of the modes described above. Theprocessing system 110 can be configured as described above with respectto FIG. 2A.

In some embodiments, the processing system 110 is further configured todetermine force information for an input object. The processing system110 can determine the force information in response to absolutecapacitive measurements obtained from sensor electrodes integratedwithin a display device. As described further below, a display device ofthe input device 100 can bend in response to a force applied by an inputobject. The bending of the display device results in a deflection fromequilibrium of at least a portion of the sensor electrodes integratedwithin the display device. The deflection of sensor electrode(s) due tothe applied force results in a change in the absolute capacitivemeasurements. The force information can include a “force images”, “forceprofiles”, or a scalar force value, depending on the configuration ofthe sensor electrodes. For example, absolute capacitive measurementsderived from the sensor electrode pattern 250B can be used to generateforce images or force scalar values. In another example, absolutecapacitive measurements derived from the sensor electrode pattern 250Acan be used to generate force profiles or force scalar values. In eithercase, the force information can be combined with position information todetermine both position of an input object and a force applied by theinput object. In another embodiment, the magnitude of the force can bemeasured to determine a scalar force value. The scalar force value canbe combined with position information to generate a force image or aforce profile.

FIG. 3 is a block diagram depicting a cross-section of the input device100 according to an embodiment. The input device 100 includes an inputsurface 301, a display cell 314A, a backlight 308, an airgap/compressible layer 310, and at least one conductive electrode(conductive electrode(s) 312). The input surface 301 can include atransparent substrate, such as a glass substrate. The conductiveelectrode(s) 312 can be metal electrode(s). In an embodiment, theconductive electrode(s) 312 includes a single conductive backplane. Inanother embodiment, a conductive backplane can be subdivided intoportions, and the conductive electrode(s) 312 can include the portionsof the conductive backplane. The conductive electrode(s) 312 can beelectrically coupled to a reference voltage, such as electrical groundor system ground.

In an embodiment, the display cell 314A includes a color filtersubstrate 302, inner layers 305, and a thin-film transistor (TFT)substrate 306. The inner layers 305 can include various layers, such asa color filter layer, liquid crystal display (LCD) material layer,conductive layers, dielectric layers, and the like. In particular, theinner layers 305 include one or more conductive layers forming sensorelectrodes 304. The color filter substrate 302, the inner layers 305,and the TFT substrate 306 are flexible such that the display cell 314Ais flexible.

The sensor electrodes 304 can have various configurations. In oneexample, the sensor electrodes 304 can include the plurality of sensorelectrodes 260 in the sensor electrode pattern 250A. In one example, thesensor electrodes 304 can include the plurality of sensor electrodes 260and the plurality of sensor electrodes 270 in the sensor electrodepattern 250A. In another example, the sensor electrodes 304 can includethe sensor electrodes 210 in the sensor electrode pattern 250B. In anyconfiguration, each of the sensor electrodes 304 comprises at least onecommon electrode configured for display updating and capacitive sensing.

The display cell 314A is disposed between the input surface 301 and thebacklight 308. The display cell 314A is flexible and can flex or bendwhen force is applied to the input surface 301. In the present example,the conductive electrode(s) 312 are separated from the backlight 308 bythe air gap/compressible layer 310, which can either be an air gap or acompressible layer 310. Accordingly, the sensor electrodes 304 aredisposed between the input surface 301 and the conductive electrode(s)312. The sensor electrodes 304 are configured to deflect toward theconductive electrode(s) 312 as the display cell 314 bends into the airgap/compressible layer 310 in response to a force applied to the inputsurface 301. Depending on the location of the force applied to the inputsurface 301, at least a portion of the sensor electrodes 304 willdeflect toward the conductive electrode(s) 312 in response to theapplied force.

FIG. 4 is a block diagram depicting a cross-section of another displaycell 314B according to an embodiment. In one embodiment, the displaycell 314B can be used in place of the display cell 314A. In the displaycell 314B, receiver electrodes 316 are disposed on the color filtersubstrate 302. In an embodiment, the sensor electrodes 304 can includethe plurality of sensor electrodes 260 operating as transmitterelectrodes, and the receiver electrodes 316 can include the plurality ofsensor electrodes 270, of the sensor electrode pattern 250A. In anotherembodiment, the receiver electrodes 316 are disposed within the innerlayers 305, rather than on the color filter substrate 316. In yetanother embodiment, the receiver electrodes 316 are disposed on the samelayer as the sensor electrodes 304.

FIG. 5 is a block diagram depicting a cross-section of the input device100 according to another embodiment. In the present embodiment, theconductive electrode(s) 312 are disposed below the display cell 314 andabove the backlight 308. For example, the conductive electrode(s) 312can be disposed below the TFT substrate 306. The conductive electrode(s)304 are separated from the display cell 314 by the air gap/compressiblelayer 310. The display cell 314 can comprise the display cell 314A, thedisplay cell 314B, or the like.

Other types of flexible display cells can be used in the embodiments ofFIGS. 3-5, such as an OLED display. In general, the display cell caninclude display pixels formed from LEDs, OLEDs, plasma cells, electronicink elements, LCD components, or other suitable display pixel structurescompatible with flexible displays. The sensor electrodes 304 aredisposed within the display cell and are deflected toward the conductiveelectrode(s) 312 when force is applied that bends the flexible display.

FIG. 6 is a schematic cross-section depicting a force applied to theinput device 100 by an input object according to an embodiment. Theinput object (e.g., a finger) applies a force to the input surface (notshown in FIG. 6), which in turn bends the display cell 314. The sensorelectrodes 305 disposed within the display cell 314 deflect toward theconductive electrode(s) 312. FIG. 7 is a top view of the input device100 given the applied force shown in FIG. 6. In the example of FIG. 7,the sensor electrodes 304 include the sensor electrodes 210 of thesensor electrode pattern 250B. The portion of the sensor electrodes 210within area 702 deflect towards the conductive electrode(s) 312 inresponse to the applied force. While the sensor electrode pattern 250Bis shown in the example, other sensor electrode patterns can be employed(e.g., the sensor electrode pattern 250A). In general, a given forceapplied to the input device 100 causes at least subset of the sensorelectrodes 305 to deflect towards the conductive electrode(s) 312. Inthe example of FIG. 7, the conductive electrode(s) 312 include a singlebackplane, but other configurations can be employed as described above.In an embodiment, the surface area of the conductive electrode(s) 312 islarger than a surface area of each of the sensor electrodes 305.

FIG. 8 is a flow diagram depicting a method 800 of operating anintegrated display device and capacitive sensing device according to anembodiment. The method 800 can be performed by the processing system 110described above to determine force information or both force informationand position information for an input object interacting with the inputdevice 100. In an embodiment, processing system 110 performs all or aportion of the method 800 during a non-display update time, such as avertical blanking time or a horizontal blanking time. In anotherembodiment, the non-display update time can be a long horizontalblanking period that occurs between display line updates of a displayframe and is at least as long as the display line update period. In someembodiments, one non-display update period can be used for force sensingand other non-display update period can be used for touch sensing,

The method 800 begins at step 802, where the processing system 110operates sensor electrodes for capacitive sensing. Various techniquesfor capacitive sensing have been described above, such as absolutecapacitive sensing and transcapacitive sensing for either the sensorelectrode pattern 250A or the sensor electrode pattern 250B.

At step 804, the processing system 110 drives the sensor electrodes forabsolute capacitive sensing. Techniques for absolute capacitive sensinghave been described above. The sensor circuitry 204 can drive the sensorelectrodes 260 or the sensor electrodes 210 for absolute capacitivesensing. In an embodiment, at step 806, the processing system 110 canalso drive the sensor electrodes for transcapacitive sensing. Techniquesfor transcapacitive sensing have been described above. For the sensorelectrode pattern 250A, the sensor circuitry 204 can drive the sensorelectrodes 260 with transmitter signals while receiving resultingsignals from the sensor electrodes 270. For the sensor electrode pattern250B, the sensor circuitry 204 can drive some sensor electrodes 210 withtransmitter signals while receiving resulting signals from other sensorelectrodes 210.

At step 808, the processing system 110 determines changes in absolutecapacitance of at least a portion of the sensor electrodes. At step 810,the processing system 110 determines force information for an inputobject based on the changes in absolute capacitance. As described above,in response to a force applied to the input device 100, a portion of thesensor electrodes in the flexible display deflect toward the conductiveelectrode(s). The absolute capacitance of such deflected electrodeschanges as those electrodes deflect toward the conductive electrode(s).By measuring this change in absolute capacitance, the processing system110 can determine force information.

At step 812, the processing system 110 can also determine positioninformation for the input object based on the absolute capacitivemeasurements and/or transcapacitive measurements. The processing system110 can combine the position information and the force information todetermine the location of the input object and the force being appliedto the input device 100 by the input object.

The embodiments and examples set forth herein were presented in order tobest explain the embodiments in accordance with the present technologyand its particular application and to thereby enable those skilled inthe art to make and use the invention. However, those skilled in the artwill recognize that the foregoing description and examples have beenpresented for the purposes of illustration and example only. Thedescription as set forth is not intended to be exhaustive or to limitthe invention to the precise form disclosed.

In view of the foregoing, the scope of the present disclosure isdetermined by the claims that follow.

I claim:
 1. An integrated display device and capacitive sensing devicehaving an input surface, comprising: a plurality of sensor electrodes,each of the plurality of sensor electrodes comprising at least onecommon electrode configured for display updating and capacitive sensing;a thin-film transistor (TFT) substrate disposed below the plurality ofsensor electrodes; at least one conductive electrode disposed below theTFT substrate, wherein the plurality of sensor electrodes are disposedbetween the input surface and the at least one conductive electrode andwherein the plurality of sensor electrodes are configured to deflecttoward the conductive electrode; a processing system, coupled to theplurality of sensor electrodes, configured to: detect changes inabsolute capacitance of at least a portion of the plurality of sensorelectrodes; and determine force information for an input object based onthe changes in absolute capacitance.
 2. The device of claim 1, whereinthe at least one conductive electrode comprises a plurality ofconductive electrodes.
 3. The device of claim 1, wherein a surface areaof the at least one conductive electrode is larger than a surface areaof each of the plurality of sensor electrodes.
 4. The device of claim 1,wherein the processing system is configured to determine positionalinformation for the input object proximate the input surface based onthe changes in absolute capacitance.
 5. The device of claim 1, furthercomprising: a plurality of receiver electrodes; wherein the processingsystem is configured to: drive the plurality of sensor electrodes withtransmitter signals while receiving resulting signals from the pluralityof receiver electrodes; and determine positional information of an inputobject proximate the input surface based on the resulting signals. 6.The device of claim 1, wherein the processing system is configureddetect the changes in absolute capacitance during a non-display updatetime.
 7. The device of claim 1, further comprising: a backlight disposedbelow the TFT substrate; wherein the at least one conductive electrodeis disposed below the backlight.
 8. A processing system for anintegrated display device and capacitive sensing device having an inputsurface and a thin-film transistor (TFT) substrate, the processingsystem comprising: sensor module comprising sensor circuitry configuredto operate a plurality of sensor electrodes, each of the plurality ofsensor electrodes comprising at least one common electrode configuredfor display updating and capacitive sensing; and a processing circuit,coupled to the sensor circuitry, configured to: detect changes inabsolute capacitance of at least a portion of the plurality of sensorelectrodes; and determine force information for an input object based onthe changes in absolute capacitance, wherein the plurality of sensorelectrodes are disposed between the input surface and at least oneconductive electrode, the at least one conductive electrode disposedbelow the TFT substrate, and wherein the plurality of sensor electrodesare configured to deflect toward the conductive electrode.
 9. Theprocessing system of claim 8, wherein the at least one conductiveelectrode comprises a plurality of conductive electrodes.
 10. Theprocessing system of claim 8, wherein a surface area of the at least oneconductive electrode is larger than a surface area of each of theplurality of sensor electrodes.
 11. The processing system of claim 8,wherein the processing circuit is configured to determine positionalinformation for the input object proximate the input surface based onthe changes in absolute capacitance.
 12. The processing system of claim8, wherein the sensor circuitry is coupled to a plurality of receiverelectrodes, the sensor circuitry configured to drive the plurality ofsensor electrodes with transmitter signals while receiving resultingsignals from the plurality of receiver electrodes, and wherein theprocessing circuit is configured to determine positional information ofthe input object based on the resulting signals.
 13. The processingsystem of claim 8, wherein the processing circuit is configured detectthe changes in absolute capacitance during a non-display update time.14. A method of operating an integrated display device and capacitivesensing device having an input surface and a thin-film transistor (TFT)substrate, the method comprising: operating a plurality of sensorelectrodes for capacitive sensing, each of the plurality of sensorelectrodes comprising at least one common electrode configured fordisplay updating and the capacitive sensing, wherein the plurality ofsensor electrodes are disposed between the input surface and at leastone conductive electrode, the at least one conductive electrode disposedbelow the TFT substrate, and wherein the plurality of sensor electrodesare configured to deflect toward the conductive electrode; detectingchanges in absolute capacitance of at least a portion of the pluralityof sensor electrodes; and determining force information for an inputobject based on the changes in absolute capacitance.
 15. The method ofclaim 14, wherein the at least one conductive electrode comprises aplurality of conductive electrodes.
 16. The method of claim 14, whereina surface area of the at least one conductive electrode is larger than asurface area of each of the plurality of sensor electrodes.
 17. Themethod of claim 14, further comprising: determining positionalinformation of the input object based on the changes in absolutecapacitance.
 18. The method of claim 14, further comprising: driving theplurality of sensor electrodes with transmitter signals while receivingresulting signals from a plurality of receiver electrodes; anddetermining positional information of the input object based on theresulting signals.
 19. The method of claim 14, the changes in absolutecapacitance are detected during a non-display update time.